1. Field of the Invention
This invention is in the field of performance of visual field tests and other tests of visual function, for the diagnosis of eye conditions.
2. Background Information
On a world-wide basis, glaucoma is one of the leading causes of blindness. Unlike cataract blindness, which is correctable with modern surgical techniques, blindness from glaucoma is permanent. The target organ of glaucoma is the optic nerve, which transmit signals of light from the retina to the brain. No known method is available for repairing, or transplanting, an injured optic nerve.
A major diagnostic problem is that visual loss from glaucoma is almost without exception painless. The patient is not aware of the ravages of glaucoma until it is too late. To compound the problem, the intraocular pressure in glaucoma is often not elevated (termed "low-tension" glaucoma), and therefore reliance upon tonometry to measure the patient's intraocular pressure frequently leads to a blatantly false sense of security. The patient is told that glaucoma is not present, when, in reality, the disease is insidiously attacking the patient's optic nerve, causing irreversible neurological damage to the visual system.
Visual field testing is mandatory for glaucoma diagnosis and treatment. The current gold standard of measurement of optic nerve function is visual field testing, called "perimetry." A problem with this technology, however, is that far too many of the examiners performing visual field testing are inadequately trained to recognize subtle patterns in the patient's visual field indicative of glaucoma (or other neurological disease). Such misdiagnosis, which is unfortunately frequent, again gives the patient a false sense of security.
Millions upon millions of patients throughout the world have glaucoma and are completely unaware of this. The particularly sad aspect of glaucoma blindness is that it is generally preventable with proper diagnosis and treatment. The proposed invention, which incorporates the use of telemedicine for real-time feedback and for autointerpretation of visual field performance, will play a major role in eliminating the all-too-common errors in visual field interpretation and the unnecessary blindness which accompanies such ignorance. By making the proper diagnosis virtually instantaneously over the Internet or other telemetric vehicle, glaucoma treatment can be instituted. Millions of patients will be spared the ravages of glaucoma.
In addition to testing for glaucomatous damage to the optic nerve, visual field testing is also used to test for a variety of neurological disorders, including cerebrovascular accidents ("strokes"), trauma, brain tumors, and other diseases. The proposed invention, which incorporates real-time feedback to monitor the patient's performance, and accurate, instantaneous diagnosis available through autointerpretation on a world-wide telemetric basis, addresses a major medical need.
With the huge data base developed by a large-scale, world-wide telemedicine system, leading international experts on glaucoma and other neurological diseases can be employed to improve the accuracy of the entire system.
Investigational work has been done on the use of neural nets "trained to interpret the visual fields from an automated perimeter," as described in "Interpretation of Automated Perimetry for Glaucoma by Neural Net," by Goldbaum, et al. Spenceley, et al. have also published work in the field in an article entitled, "Visual Field Analysis Using Artificial Neural Networks." Brigatti, Hoffman, and Caprioli have worked with neural networks for glaucoma identification, as described in their article entitled, "Neural Networks to Identify Glaucoma With Structural and Functional Measurements." These works are limited to conventional globe-like perimeter systems.